The Caoling railway tunnel was decommissioned more than 30 years ago, but has never seen so much traffic. The 2.1km tunnel, on Taiwan’s rugged east coast, is proving a hit with locals forced by coronavirus restrictions to holiday domestically, especially on the weekends. The tunnel attracts as many as 2,400 cyclists every Saturday and Sunday, says Deng Kuang-jung, of the Northeast Coast and Yilan National Scenic Area Administration. In fact, the cool tunnel air and the adrenaline rush of a flattish half-hour ride have proven so irresistible that volunteers enlisted by the administration sometimes have to ask riders to stop before entering the tunnel and wait until the traffic inside thins out, Deng says. Cycling trips that pass through the tunnel normally start at Fulong Station, a railway stop about 90 minutes east of Taipei . Outside the station are 10 cycle rental shops. The owner of one of them, Lin Po-ching, tells us why the tunnel is so popular: “You get to the entrance and it’s 22 degrees Celsius, so it’s fun to stop – and comfortable.” Winds from the south cool the tunnel, keeping the temperature about 10 degrees lower than outside. From Fulong, riders take a two-lane road that follows railway tracks east past farms and tracts of rainforest. The tunnel entrance pops up after about 2km. Beside it are another three rental shops, which cater for visitors who have parked their cars nearby. Cycling in Cambodia: what a bike trip to Phnom Penh’s newest tourist attraction reveals Many riders stop outside the tunnel mouth for a photo with a preserved section of railway track, complete with aged stop-go light, set aside in a tiny park. Taiwan’s Japanese colonial government built the single-track tunnel in 1924 as part of a project to smooth railway traffic between the isolated, mountainous east coast and urban Taipei. After a new, wider tunnel opened metres away in 1986, the old one was abandoned. It was reopened for bikes in 2011. Their photos taken, riders turn south and pass under the arched tunnel entrance, which is rimmed by the palmetto palms common to Taiwan’s rainforests. Inside, lights similar to those found in road tunnels are spaced along each wall, about 15 metres apart. “Taiwan has lots of tunnels but not like this, with a clear [lit] view,” says Hsieh Yen-sih, 21, a student at the National Cheng Kung University who is enjoying the ride with two older relatives. Ahead, cyclists in skintight, sweat-repellent jerseys swerve their expensive road bikes around tween girls in summer dresses and their grandparents in floppy sun hats, who are pushing more slowly through the tunnel, which is about two standard bike lanes wide. Children ride on the back of tandems, helping to pedal. Grandparents prefer e-bikes. The sound from their motors mingles with the whoops of pleasure echoing off the tunnel walls. Along one section, classical Chinese music issues from hidden speakers. Clusters of riders dismount deep inside the tunnel for photos at vertical columns of white lights marking the border between New Taipei City, which includes Fulong, and Yilan County to the south. Kao Wei-cheng, 25, a student at National Taiwan University, is enjoying himself, but worries about congestion in the tunnel. “Sometimes e-bikes and pedal bikes are moving in the same lane, not separated, so it’s dangerous. We go at different speeds,” he says. At the southern end, most riders pull over and sit on benches along a wooden promenade and cement platform to view the Pacific Ocean below and uninhabited Guishan Island, which is shaped like a partly submerged turtle. Occasionally, a train whizzes past them, having exited the new tunnel. The bike path continues, but most families turn around here, after buying cold drinks and ice cream from a row of vendors, and pedal back into the cool confines of the Caoling tunnel.